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Q: Is their anything special I should be looking for with the batteries.
I understand that they must be AA size and approx 500 mAh. Is their anything else? Can you guys recommend a (quality) brand.

Not looking forward to this open heart surgery, but I really do want to get rid of the rotten constantly glowing Oil Service & Inspection service lights which also won't reset properly, erratic fuel econogauge and faulty oil temp gauge.

I've researched a fair bit and I believe replacing the NiCads will more than likely do the trick.

Any info from members who've actually done this and what I should/shouldn't be doing.

Oh well, the thread's not that old and I need help 'n $h!t. Funny thing is, I replaced the SI board batteries about 7 or 8 years ago (the tach had stopped) and now I'm wondering how I was skilled enough to do so. I can barely remember it. They say memory's the second thing to go and I forget what the first one is. This is a new speedo cluster, well, new/used. Mine was registering miles too slowly on the odo. 40 mile trips would register 15. After putting the new one in, the tach wouldn't work and then all of a sudden it would work. The speedo and odo worked fine, it was registering accuarte miles. Then the tach stopped(few weeks later) and a few days ago, the odo stopped as well. Not slow like my old one but not moving period.

In an earlier thread and elsewhere, I've seen reference to odo gears. This is puzzling to me as this cluster is all electric. There is no cable from the tranny like I've seen with more primitive cars in the past. So how would gears be used in an electric odo? Is it maybe to reduce the speed of some motor to the proper speed for turning the wheels?

At any rate, would utterly dead SI batteries render the odo dead as well? This unit sat on a shelf for several years. I'm wondering if the batteries went bad owning to no use, no charging I mean. I'm going to buy a couple batteries and put them in. I just hope I can solder them as well as I did back when.

BMW triggered the Speedometer by electronic pulses and then drove the odo by gears
There are various issues by British Motor Works that have me puzzled to no end
There is only one option apart from accepting it & that is

I would not know where to get NiCd from anymore, so I am going to pop in NiMH batteries.

BMW triggered the Speedometer by electronic pulses and then drove the odo by gears
There are various issues by British Motor Works that have me puzzled to no end
There is only one option apart from accepting it & that is

I would not know where to get NiCd from anymore, so I am going to pop in NiMH batteries.

dont do this. you need to get the right ones. it will probably work for a few years, but certainly wont last another 15 or 20. The charging circuit is not designed for it, and each cell puts out a different power, usually different voltages i forget whether NiCd is higher than NiMH or other way around

The industrial, gritty town of Berkeley, CA is home to a nifty story, Al Lasher Electronics, and they have become the go to spot for SI batteries. The guy told me to take mine apart first, so as to get the correct batteries. I'm pretty sure these are NiCds but they'll know.

Since I now got the parts for my Project 323, I decided to look at the SI board battery issue. And did not find anything remotely looking like normal AA NiCd batteries
Those in there are clearly Lithium type.
These CR142 50 SE are also noticably shorter & fatter than the usual NiCd AA type.
Now I am not sure whether they have to be replaced yet, as they show 2.83v after 3 months of not getting power ?

There are exact replacement batteries available. Remove cluster from dash, on backside remove panel- multiple nuts holding cover on. SI board at bottom of cluster. Batteries are soldered onto board. Look at batteries and get exact part number and call a local battery shop in your town. They will be able to match, My 87 325e had 2 1.5 volt lithium type batteries MnO2-li. Part number from a battery distributor in Everett WA is "COMP-7-3" He said they cost about 11$ each + 5$ shipping. If you know how to solder old batteries can be removed & replaced for much less than a refurbished SI board. It is important that you get the exact part number & MFR info off the batteries in your cluster. I would suggest you take the SI board to the battery distributor for reference.

Thanks for your reply
I was under the impression all ran rechargeable AA type batteries till you now enlightened me
I had to remove the cluster etc. to post that picture of my SI board batteries.
Battery shop in Namibia ? Sadly everything (except food) has to be imported
I just wonder if this is the corect SI board/batteries/cluster set-up for this vehicle The vehicle is old & had a few "mechanically minded" fellows work on it.

Thanks for your reply
I was under the impression all ran rechargeable AA type batteries till you now enlightened me
I had to remove the cluster etc. to post that picture of my SI board batteries.
Battery shop in Namibia ? Sadly everything (except food) has to be imported
I just wonder if this is the corect SI board/batteries/cluster set-up for this vehicle The vehicle is old & had a few "mechanically minded" fellows work on it.

That part # looks correct. Before you pull the batteries off board make sure that all the fuses are ok. My gauge cluster stopped working so I figured it was the batteries. I pulled the batteries and installed a remote 2 AA battery pak holder and new batteries, the gauges still did not work. Fuse # 10 failed twice, I still haven't determined why but after the third fuse was installed it held and the gauges started to operate properly. There are many functions that fuse # 10 controls. This is the first BMW I have worked on, it can be very frustrating and time consuming. A long learning process.

Mine are marked Laser Lithium MnO2-Li Battery CR1425 OSE (3V)
The 14250 is a standard primary (non-rechargeable) Lithium cell.
I have researched an equivalent in a Sanyo CR14250 SET-FT 3V 850mAh 14.5x25mm (1/2 AA size) lithium cell.
Sadly these are not available in Namibia or Cape Town